A conventional seat slide apparatus for a vehicle is described in Japanese Patent No. 2005-225415 A (hereinafter, referred to as a reference 1). As illustrated in FIG. 1 of the reference 1, the seat slide apparatus for the vehicle includes a pair of lower rails, a pair of upper rails, a lock mechanism (a locking lever member), a releasing lever (opening bracket), a second biasing member (springs), and a handle (handle). The lower rails are secured to a vehicle floor, while the upper rails are secured to a vehicle seat and are longitudinally movably supported relative to the lower rails. The lock mechanism is provided at the lower rail and includes plural lock portions (lock bores), a lock member (a locking lever) and a first biasing member (a torsion spring). The lock portions (lock bores) are longitudinally provided at the lower rail and are arranged in line. The lock member (locking lever) is provided at the upper rail and is pivoted around a pivotal shaft line which extends in a longitudinal direction of the upper rail. Further, the lock member (locking lever) is engageable with and releasable from the lock portions (lock bores). The first biasing member (torsion spring) biases the lock member (locking lever) in a direction where the lock member (locking lever) is engaged with the lock portions (lock bores). The releasing lever (opening bracket) operates the lock member (locking lever) to be pivoted and releases the lock member (locking lever) from engaged with the lock portions (lock bores). Further, the second biasing member (spring) biases the releasing lever (opening bracket) in a direction where the lock member (locking lever) is to be engaged with the lock portions (lock bores). The handle (loop handle) is arranged to operate the releasing lever (opening bracket).
According to the seat slide apparatus for the vehicle described in the reference 1, the lock member (locking lever) is biased by the first biasing member (torsion spring) in a direction where the lock member (locking lever) is engaged with the lock portions (lock bores). Therefore, when the handle (loop handle) is not operated, the upper rail is locked to the lower rail. Further, the second biasing member (spring) biases the releasing lever (opening bracket) in a direction where the lock member (locking lever) is engaged with the lock portions (lock bores). Accordingly, when the vehicle is being driven, the releasing lever (opening bracket) does not repeat separating from nor connecting with the lock member (locking lever) and an unusual noise is prevented from being generated.
However, the conventional seat slide apparatus for the vehicle requires not only the first biasing member (torsion spring) but also the second biasing member (spring). Therefore, an amount of components is increased and furthermore, an assembling procedure is not facile.
A need thus exists for a seat slide apparatus for a vehicle which is not susceptible to the drawback mentioned above.